Magnetic separator



Aug. 10, 1943. R. H. sTEARNs .K 2,326,575

MAGNETIC SEPARATOR Filed April 1o, 1939 5 sheets-sheet 1 ATTORNEY.

Aug. 10, 1943. R. H. sTEARNs MAGNETIC SEPARATOR Filed April 10, 1939 5 Sheets-Sheet 2 INVENTOR #05u/fu JMA/mu Aug. 10, 1943. R. H. sTEARNs MAGNETIC SEPARATOR Filed April l0, 1939 5 Sheets-Sheet 5 1N VENTOR Jam/fu JffAAD/VJ Patented ug. l0, i943 MAGNETIC saPARA'roR Roswell H. Stearns, Wauwatosa, Wis., assignor to Stearns Magnetic Mfg. Co., Milwaukee, Wis., a corporation of Wisconsin Application April 10, 1939, Serial No. 267,113`

6 Claims.

This invention relates to magnetic separators.

Objects of this invention are to provide magnetic separator constructions which are so made that a multitude of localized travelling magnetic fields are produced, and in which these magnetic fields are of extreme intensity and substantially instantly appear and disappear, thereby avoiding any residual magnetic effects.

Further objects are 4to provide a novel magnetic separator in which a rotary drum is employed, and in which the primary magnet is located within the drum and so organized and arranged with respect to the drum that a narrow localized, intense magnetic field is produced in a zone transversely of the drum, and in which the drum itself is so made that the multitude of magnetic elds hereinabove described are produced at the outer periphery of the drum and travel through the intense zone of the primary magnet, and in which these localized intense travelling magnetic zones exist substantially only at the main magnetic zone extending transversely of the drum.

Further objects are to provide a construction oi magnetic separator having the characteristics hereinabove described which nevertheless may be very easily manufactured, which is of relatively simple construction and one that is reliable in its operation.

In greater detail, objects of this invention are to provide magnetic separators which utilize wire wound on the outer surface of a drum, which employ the wire in a novel and highly advantageous manner to provide the quickly responsive magnetic or active portions of the separator to thereby secure in a simple and highly eiective manner a multitude of concentrated peripherally travelling magnetic fields without having any axial shift, and to provide a construction which utilizes magnetic wire in a practical and simple manner readily lending itself to ordinary manuf acturing practices.

Embodiments of the invention are shown in the accompanying drawings, in which:

Figure 1 is a sectional 'view on the line l--I of Figure 2 showing one form of the invention.

Figure 2 is a sectional View on the line 2 2 of Figure 1.

Figure 3 is a sectional View of a further form of the invention, such view corresponding to a section on the line 3-3 of Figure 4.

Figure 4 is a sectional view on the line linof Figure 3.

Figure 5 is a sectional view showing a further form of the invention.

Figure 6 is a sectional view showing a still fur- Y ther form of the invention.

Figure 7 is a fragmentary detail showing a section through one of the drums and the magnetic wires thereon.

Figure 8 is a sectional detail showing a further form that the magnet may take.

Figure 9 is a fragmentary detail showing the joint in the sealing gasket.

Figure l0 is a detail of a locking support or bearing.

Referring to the form of invention shown in Figures 1 and 2, it will be seen that the magnet comprises what may be called a closed circuit magnet. It is provided with a central core I terminating in a pointed lower pole 2. The yoke of the magnet is indicated by the reference character 3 and continues downwardly vto provide two poles which are also tapered and are closely adjacent the tapered tip of the pole 2.

It is to be noted that the outer circumference of the yoke 3 and poles 4 is circular and is arranged within a rotary drum indicated generally by the reference character 5. This rotary drum comprises a non-magnetic shell 6 upon Which magnetic wire is wound. This magnetic wire is relatively soft and is easily magnetized. It is wound without spacing tighty upon the outer surface of the non-magnetic shell 6. In this manner these magnetic wires constitute a very thin magnetic shell closely adjacent the concentrated field which is produced by the close approximation of the poles 2 and 4. Although round wires have been shown, nevertheless Wires of other shapes may be employed. The magnet is adapted to be energized by means of the winding 8 so that a very powerful magnetic field is produced in a highly restricted zone adjacent the lower portion of the drum, as is obvious from an inspection of Figure 1.

The drum is carried by rotary heads 9 to which the shell 6 is rigidly attached. These heads 9 are sealed in a Water-tight manner to the drum by providing a yielding gasket Ill at each end of the drum, see Figure 2, such gasket being of rubber or other suitable material. 'Ihe gasket is drawn .into sealing engagement with the drum and with the heads by means of the annular anged members H. Bolts l2 extend through the heads 9 and are threaded into the flanged members Il so that the gasket In may be highly compressed and may form a water-tight seal between the shell and the heads. The gasket has its ends tapered, as shown in Figure 9, so as to form a complete seal al1 the Way around the drum at each end thereof.

'I'he drum may be rotated in any suitable manner as, for example, by a driving pulley I3 rigid with one of the heads as shown in Figure 2. It is mounted for rotation upon hollow shafts I4 which are carried in fixed supports or locking bearings I5, adjacent the revoluble heads 9. These bearings are shown in greater detail in Figure and it will be seen from such figure that they are provided with a split or cut portion I6 and with a locking screw I1 so that they may be clamped tightly upon the shafts I4 and thus lock the shafts in any desired adjusted position. The purpose of this will hereinafter appear. The hollovv shafts I4 carry non-magnetic transverse supporting members I4 which are securely bolted to the yoke portion of the magnet and thereby support the magnet. dicated at I8 in Figure 2, between the heads 9' and the shafts I4. Sealing means I9 and 20 are provided between the heads 9 and the shafts I4.

'I'he conductors leading to and from the magnetizng Winding 8 are indicated at 2| and extend outwardly through one of the hollow shafts I4. Preferably one of the hollow shafts is provided with one or more radially extending openings 22 so that a bar or Spanner wrench may be inserted in the opening to turn the shafts a slight amount after the clamping screws I1, see Figure 10, have been loosened. The purpose of this is to adjust the exact point of the intense magnetic field wherever found most desirable for the particular material then being handled by the separator.

In the form of the invention shown in Figures 1 and 2 either a dry or wet feed may be employed. In the form chosen for illustration the material is fed by means of a strean of water passing inwardly into the distributor pipe 23 and upwardly into contact with the lower portion of the drum so that the material will directly contact with the saturated or highly magnetized magnetic wires. A plurality of vertically arranged baiiies 24 may be provided for causing uniform distribution of the material. The overflow occurs on either side of the distribution pipe or supply pipe 23, as may be seen from Figure 1, and the non-magnetic material and water overflows and is caught in the trough like portion 25 and lead outwardly through the discharge opening 26.

The magnetic material adheres to the highly magnetized magnetic wires of the drum and as the drum rotates in the direction shown in Figure 1, is carried past and falls from the drum into the compartment 21, a suitable rotary rubber or other wiper or brush like member 28 being provided to strip any adhering material form the drum. The magnetic material is discharged at the point 29, see Figure 1. If desired, the action of the stripper 28 may be supplement-ed by a spray, as will be described for a further form of this invention.

In the operation of the separator the magnetic portion of the material to be separated may be either of high permeability or of low permeability. It is attracted into direct contact with the highly magnetized magnetic wires. The magnetic material will be readily discharged, however, from the drum as there is a very sharp cut-off of the magnetic flux and the magnetic wires do not retain any appreciable residual magnetism, the material freely dropping after it has passed the dividing partition or portion 310 into the compartment 21. It is to be noted particularly that Suitable bearings are provided, as in-k there is a very highly concentrated field at the bottom portion of the drum extending transversely across the drum in a substantially straight line and that the magnetic wires on the outer side of the drum are very highly magnetized.

In the operation of the device these magnetic wires are usually in a, saturated-condition and it is to be noted further that, due to the fact that round or other shaped wires are used, the round wires being shown in enlarged fragmentary detail view, Figure "1, a multitude of concentrated zones are produced circumferentially of the drum, in addition to the main highly concentrated line of flux transversely of the drum.

The above result is due to the fact that magnetic flux tends to concentrate at the projecting portions of a magnet structure, for example from the protruding outer rounded portions of the magnetic wires. Consequently there is an extremely high concentration of flux peripherally of the magnet drum in the relatively narrow, intense transverse flux zone,

The separator operates by actually lifting and -holding the magnetic material and it has been found that not only magnetic material of high or medium permeabilitybut also magnetic material of very low permeability may be readily separated from non-magnetic material by the operation of this separator. Further it has been found that the concentration of flux is in a relatively small zone and is very high indeed. This zone extends, as described, transversely across the drum. The particular point at which the zone is formed may be adjusted by loosening the clamping screws I1, see Figure 10, and rotating the magnet structure, at least one of the shafts I4 being accessible for this purpose, as described and as shown in Figure 2. This adjustment of the point at which the transverse magnetic zoney will be formed may be made while the machine is in actual operation, if so desired. After the correct adjustment has been made the clamping screws I1 are again tightened to hold the mag-net structure in its adjusted position.

It is to be noted that the shafts I4 are hollow and air is blown through the drum for the double purpose of cooling the magnet and also of drying the interior of the drum from any condensation of the moisture of the air, for it is apparent that the feed Water carrying the mixture of magnetic and non-magnetic material to the drum will chill the drum and might tend to precipitate moisture from the air interiorly of the drum. The interior of the drum is kept absolutely dry by the sealing gaskets heretofore described and by the circulation of air therethrough.

The concentration of flux, it is to be noted, is at one fixed line transversely of the drum. There is no axial shift of the flux at the drum surface as the drum rotates. Also it is to be noted that by using the magnetic wire, that a non-magnetic shell or drum may be provided which may be relatively thin as there is no action to distort the drum due to the direct pull of the magnet on this shell. The pull of the magnet on the relatively small magnetic wire is not sufiicient to distort the drum and consequently it is possible to have a very small air gap between the primary magnet located inside of the drum and the secondary magnet constituted of the magnetic wires in the immediatevicinity of the primary magnet poles.

A further form of the invention is shown in `'I'he magnet may be carried in the same way as previously described by means of the transverse non-magnetic members 33 which are rigidly secured to the hollowshafts 34, the shafts being carried in locking bearings or supports 35 and being adjustable in such supports. A convenient way of insuring, the centering of the magnet within the drum indicated generally at 36 may be secured by turning or machining a ange 31 53 upon which the magnetic wires 54 are wound.. The magnet has the axis of its core` 55 and of its magnetizing winding 56 set at an angle to. the vertical and has a relatively short lower pole piece 51 and a relatively long pole piece 58 ex- 1 tending from the upper end of the vcore downonopposite sides of the magnet structure and by machining the ends of the transverse yoke pieces o r supporting pieces 33 to substantially the same .radius so that they will always correctly center the magnet with reference to the drum. The same construction could be used in any of the several forms of the invention.

The ydrum' 36 consists, as previously described,

' of the non-magnetic shell 38 which -is wound with magnetic wire 39. The drum is carried by rotary heads 40 and may b'e sealed to these rotary heads in the same manner as described in connection with the form shown in Figures 1 and 2 by means of the sealing gaskets 4l.-

The shafts 34 are hollow and the conductors leading to the magnet coil 42 pass outwardly Air from ya suitable source of supply is blown through these hollow through one of the shafts.

shaftsand cools the magnet and maintains the inner portion of the drum dry and free from condensation. The drum may be driven as previously described or in any other suitable way, as bymeans of the friction drive roller 43. This form of the invention may be adapted for either dry or liquid feed. In the form chosen for illustration, .the mixture of magnetic and non-magnetic material is fed in a flowing stream .of water which passes down the chute 44 and into contact with the descending portion of the drum. This mixture of water and magnetic and non-magnetic material is guided and held closely adjacent the drum by means of the curved guide 45. Preferably a seriesof bailles 46 are provided for causing the material tov contact with the drum several times and to prevent the sliding of material along the guide 45 without being brought u clamping bearings 35 as previously described and rotating the magnet through the medium of one of the hollow shafts 34. This may be done while the device is in operation to secure the best or most eiicient point for the location of the transversely extending, highly concentrated magnetic zone.

A further form of the invention shown in Fig-y ure 5 will now be described. In this form of the inventionthe drum is indicated generally .at 52 and may be constructed in the same manner as previously described with a non-magnetic shell wardly into proximity to the lower pole. These pole pieces approach each other closely and are tapered adjacent their lower ends. It has been found that the concentration of ux is' greater with this style of magnet than with that shown in Figure 3 and there is a more abrupt cut-off when the drum carries the magnetic material past the lower pole. There is less leakage of flux to the left, as viewed in'Figure 5,- from the lower pole and consequently this sharp cut-off is obtained. Also the waste leakage of iiux is `materially reduced in this form of the invention aspractically all of the ux traverses the gap between the pole pieces and is useful in highly concentrating the flux and in highly'magnetizing the magnetic wires on the outer side of the drum.

'I'he incoming material is fed by means of the vibratory feeder 59 and this feeder as shown is for dry material though either the dry or wetv feed may be used in any form of the invention by suitable changes for the feed mechanism. A dividing member 60 is positioned adjacent the lower portion of the device.

It is'v apparent, that although there is some leakage and distribution of flux on the `side of the drum towards the oncoming material, this does not do any harm whatsoever. There is a very great concentration of ux'adjacent Athe pole tips and the magnet wires are very highly magnetized. F

The magnet may be adjusted as 'previously described to secure the most eiective position for the highly concentrated line of flux extendving transversely across the drum.

The invention may take the form shown in Figure 6 in which the pole pieces 6I are sym- .metrically located with reference to the core 62 and magnet winding 63. This magnet may alsov .be adjusted as previously described. `Any 'suitable type of feed for either wet. or dry'feed-mayA be employed, the vibratory feeder 64 having been shown and the dividing member 65 being shownv as previously described.

It is obvious that instead of makingthe core pieces of a single structure that they' may be made of multiple portions and that each of these portions may have its individual energizing winding with any form of the invention. This construction has been illustrated in Figure 8 as applicable to the type of magnet shown in Figure 1 for the sake of illustration. In this form of theinvention the' individual core pieces are indicated bythe reference characters 66 and each core piece is provided with its energizing winding 61. The cores extend from the upper yoke portion l68 corresponding to the Iportion r3 of Figure 1 to the lower pole piece 69 corresponding to the lower centralpole piece 2 of Figure 1, a portion of one of the side polesI being indicated at 10 in Figure 8 and corresponding to the side It will be seen that a novel vform o'f separator has been provided by this invention in which the separator lifts the magnetic material'y from u the non-magnetic material into direct contact with a highly vmagnetized portion of the drum,"

namely, the highly magnetized magnetic-wires.

"I'hisseparator in any of its forms can be used for either the wet or dry separation and the particular type of feed may be varied. to suit the particular conditions under which the separator.

is to operate. However, in all forms of the invention it is to be noted particularly that the magnetic wires are very highly magnetized at a sharply localized zone extending transversely across thedrum and that there is'a relatively sharp cut-oil' of the magnetic flux with consequent deenergzing of these magnetic wires shortly after the magnetic wires pass this highly concentrated zone of flux.

It is possible with this separator to separate either high permeability material from nonmagnetic material or low permeability material from non-magnetic material. As a matter of fact, the concentration of ux in the magnetic wires may be so great that very low permeability material may be separatedV and this action is enhanced due to the fact that the magnetic material comes in actual contact with the highly magnetized or saturated iron wires, thereby securing the maximum eiect on the low permeability material. As stated, however, the device is equally serviceable for the separation of high permeability material from non-magnetic material.

Additionally, as is apparent from an examination of Figure 7, the magnetic wires provide protuberances due to their curved or other shaped surfaces which extend outwardy beyond the general surface of the drum, and it is well known that magnetic ux concentrates at the projecting portions of a magnetic structure. Consequently there is extreme concentration o f ilux at these projecting portions, thereby enabling the device to eifectively separate magnetic material from non-magnetic material.

It is to be noted particularly that this construction provides a multitude of highly concentrated magnetic fields which are travelling, which hold the magnetic material in direct contact with the wires, and in which means are provided for securing substantialy instantaneous magnetization and demagnetization without residual magnetic effects.

It is to be noted further that in practising the invention it is possible to secure a very small air gap between the primary magnet located internally of the drum and the secondary or induced magnet formed on the outer periphery of the drum by the magnetic wires wound thereon so that a very intense magnetization of these wires is obtained.

It is to be'noted further that this invention provides external means for adjusting the magnet within the drum so as to get the zone of magnetic concentration extending transversely of the drum located at the most eective position.

It will be seen further that the invention provides a separator which may be very readily constructed and which is of relatively simple and substantial design.

Although this invention has been described in considerable detail. it is to bc understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

I claim:

l. A magnetic separator comprising a drum, a pair of revoluble heads secured to said drum, yielding gaskets between said heads and said drum, means for compressing said gaskets into sealing engagement with said drum and with said heads, an electromagnet mounted within said drum and having a pair of poles mounted in proximity to the inner periphery of said drum, shaft means extending through said heads and supporting said electromagnet, saidheads being revolubly mounted onl said shaft means, means for driving said drum, and means for feeding a mixture of a liquid and magnetic a-nd nonmagnetic material to said drum, said shaft means having air passages leading into and .out of said drum for cooling said electromagnet and ventilating the interior of said drum, whereby said electromagnet is cooled and any condensation within said drum produced by chilling from said liquid is removed by the air passing through said drum.

2. A magnetic separator comprising a nonmagnetic drum, a, magnetic outer peripheral portion carried'by said drum and forming a unitary portion with said drum, an electromagnet mounted within said drum and having a pair of opposed pole tips located in proximity to the inner peripheral portion of said drum, a pair of stationary shafts extending from opposite sides of said electromagnet for'supporting said electromagnet, a pair of heads revolubly mounted on said shafts and secured to opposite ends of said drum, yielding gaskets, means for forcing said yielding gaskets into binding engagement with said heads and with said drum, means for convolutions approximately lie in planes sub-l stantially at right angles to the axis oi the drum,

, an electromagnet located within said drum and having pole tips adjacent each other and closely adjacent the inner periphery of the drum and providing a gap between the pole tips extending substantially parallel to the axis of the drinn,

means for rotating said drum, means for feeding material to saiddrum, and dividing means adjacent said drum, the arrangement of magnetic wires and pole tips preventing axial shifting of ,magnetic material clinging to said drum while said drum isbeing rotated and providing a contending substantially axially of said drum.

4. A magnetic separator comprising a revolubly mounted drum of non-magnetic material having a layer of magnetic wire wound thereon in successive convolutions without spacing, tightly on the outer side of said drum, which convolutions approximately lie in planes substantially at right angles to the axis of the drum, an electromagnet located within said drum and having a pair of symmetrically arranged pole tips closely adjacent each other and closely adjacent the inner periphery of the drum and providing a gap between the pole tips extending substantially parallel to the axis of the drum, means for rotating said drum, means for feeding material to said drum, and dividing means adjacent said drum, the arrangement oi magnetic wires and pole tips preventing axial shifting of magnetic material clinging tol said drum while said drum is being rotated and providing a concentrated, relatively narrow magnetic zone extending substantially axially of said drum.

5. A magnetic separator comprising a revolubly mounted drum of non-magnetic material having a layer of magnetic Wire wound thereon in successive convolutions without spacing, tightly on the outer side of said drum, which convolutions approximately lie in planes substantially at right angles to the axis of the drum, an electromagnet located within said drum and having a centrally located pole tip and a pair of pole tips on opposite sides of said centrally located pole tip with the pole tips closely adjacent each other and closely adjacent the inner periphery of the drum and providing a gap between the pole tips extending substantially parallel to the axis of the drum, means for rotating said drum, means for feeding material to said drum, and dividing means adjacent said drum, the arrangement of magnetic wires and pole tips preventing axial shifting of magnetic material clinging to said drum while said drum is being rotated and providing a concentrated, relatively narrow magnetic zone extending substantially axially of said drum.

6. A magnetic separator comprising a revolubly mounted drum of non-magnetic material having magnetic Wire wound thereon, an electromagnet located within said drum and comprising a core structure having an energizing Winding thereon with the winding and core structure located unsymmetrically with reference to said drum with relatively little space between the drum and one side of said winding and relatively greater space between the other side of said winding and said drum, relatively short and long poles extending from opposite ends of said core structure and terminating in pole tips located adjacent each other and in close proximity to the inner periphery of said drum and providing a gap extending transversely across the drum, said relatively long pole being located on the side of said winding which is spaced the greater distance from said drum, means for rotating said drum, means for feeding material to said drum, and dividing means adjacent said drum.

ROSWEIL H. STEARNS. 

